Project Spotlights

The Next Performance Enhancing Drug: Sleep

We've all been there: slouching down in class, trying to peel your eyes open, suffering from that all-nighter. Especially in a college setting, sleep deprivation can be a normal part of life. Whether it is before a big exam or a project deadline, some people remain awake long after their normal bedtime to finish their work.

Although it is no secret that without a good night's sleep it is difficult to perform to the best of our ability, the effects of sleep deprivation on different types of performance variables are not well understood. Students participating in the Creative Inquiry team led by Dr. June Pilcher from the Department of Psychology are investigating the effects of sleep deprivation to better understand how sleep loss affects performance.

Dr. Pilcher's Creative Inquiry team has completed both partial and total sleep deprivation studies. The partial sleep deprivation study allowed participants to sleep at night for about four and a half hours and then complete tasks during the day. The total sleep deprivation studies required participants to remain awake overnight while completing tasks. In both types of studies, the participants completed a variety of tasks multiple times to assess changes in their performance due to sleep deprivation.

Testing participants during the day after limited sleep at night simulates partial sleep deprivation as experienced by many adults who voluntarily sleep less at night. Testing participants during the night simulates working night shifts as well as students attempting to study during an over-night "cram-fest." In both types of sleep deprivation studies, subjects became less engaged and had a decreased attention span. Performance on tasks that were less interesting (e.g., vigilance tasks such as driving a car) or tasks requiring active effort (e.g., focusing on a short term memory task) decreased under sleep deprivation conditions. Overall, the partial sleep-deprived participants performed better on the tasks than the total sleep-deprived participants; however, even partial sleep deprivation resulted in decreased performance on many of the tasks.

According to Dr. Pilcher, "What we are looking for is how we can best cope with sleep deprivation. This is particularly important under shiftwork conditions as seen in many health-care and industrial settings when the worker must be awake and functioning at night."

The Creative Inquiry team completed several studies examining reaction time and the ability to make correct choices in memory tests under sleep deprivation conditions. The team found that sleep-deprived students had slower reaction times. They were often less accurate especially on tasks that were not particularly interesting. Dr. Pilcher's team also studied the effects of sleep deprivation on language. A sample of non-native and native English speakers was evaluated. High level language processing, such as reading comprehension, was negatively affected under total sleep deprivation conditions. Meanwhile, lack of sleep had little to no effect on more basic language processing, like antonym identification.

When we think of sleep deprivation in real world settings (such as hospitals), it becomes important to consider if we can predict the effects of lack of sleep on performance. The Creative Inquiry team has completed preliminary studies to investigate this issue. They found that pupil diameter and saccadic velocity (how fast the random movements of the eyes occur) were predictive of change in performance under sleep deprivation conditions. The team theorizes that the slowing of the eye movement and pupil dilation may provide good indicators of excessive sleepiness and performance decrements found under sleep deprivation conditions.

The results found in the studies completed by Dr. Pilcher's Creative Inquiry team are useful for college students as well as society. Undergraduate Kristen Jennings noted, "Our sleep deprivation studies have provided valuable insight into the demands that sleep loss can place on individuals trying to complete various tasks. Recognizing how stress and fatigue can affect cognitive functioning and physical health is very applicable for college students and real-world workers with lifestyles commonly characterized by busy schedules and not enough sleep." All this goes to show that maybe you should just sleep on it.